Abstract: A kind of dynamic data acquisition system that aim at the production of plant was developed to aquire and analyse the character of splash in resistance sport welding(RSW) process.This system was used in the laboratory circumstance to acquire the data of RSW.The characteristics of dynamic resistance curve(DRC) were annlysed with the influemes of the welding current,electrode pressure,the surface state of workpiece and the short margin distance on the splash.The result shows that the forms of DRC and the change ratio curve,the peak value,the time of reaching at and staying at the peak,and the drop degree of the peak are different.There are some kinds of sudden change in different stage of the DRC.The earlier stage is more evident than the latter.Characteristic parameter of dynamic resistance for splash in resistance spot welding low carbon steel to some extent is reflected by the sudden change of DRC and its change ratio.